In recent years, there have been dramatic improvements in LED technology such that LEDs of increased luminance and color fidelity have been introduced. Due to these improved LEDs and improved image processing technology, large format, full color LED video screens have become available and are now in common use. LED displays typically comprise a combination of individual LED panels providing image resolutions determined by the distance between adjacent pixels or “pixel pitch.”
Outdoor displays, which are intended for viewing from greater distances, have relatively large pixel pitches and usually comprise discrete LED arrays. In the discrete LED arrays, a cluster of individually mounted red, green, and blue LEDs are driven to form what appears to the viewer as a full color pixel. On the other hand, indoor screens, which require shorter pixel pitches such as 3 mm or less, typically comprise panels carrying red, green, and blue LEDs mounted on a single electronic device attached to a driver printed circuit board (PCB) that controls the output of each electronic device.
Although both indoor and outdoor displays are viewable across a substantial range of off-axis angles, there is often a perceptible loss of color fidelity with increasing viewing angle. Additionally, the material of each LED device and/or the material used to mount each of the LEDs may have reflective characteristics, which can further decrease color fidelity by creating unwanted light reflection and/or glare.
Usually, LED displays prefer a relatively wide viewing angle so that viewers may be able to view the displayed images and videos at different angles. However, there are certain situations a narrow viewing angle is preferred. For example, when high beam intensity is preferred, LED devices with a relatively narrow viewing angle is preferred. Also, for security and privacy concerns, a user of an LED display may prefer that others around him cannot see what is displayed on his or her LED display in public places. Further, such an LED display for personal use may consume less energy compared with wide viewing angle display.